The goal of this program is to advance the understanding of the pathology underlying the Sudden Infant Death syndrome, with particular reference to sleep and sleep-related disorders. Twenty-four hour polygraphic monitoring in "near miss" for SIDS infants revealed that mixed and obstructive respiratory events are more numerous than in control infants. These events are associated with cardiac changes during sleep. One infant monitored 24 hours before SID also had an abnormal high number of mixed and obstructive events during sleep compared to normal controls. Autopsy demonstrated no cause for this polygraphic finding. After 9 months of age, most "near miss" infants seem to have normal sleep monitoring compared to controls. Systematic studies have revealed neurological abnormalities in infants "near miss" for SIDS. A longitudinal study comparing polygraphic variables during sleep (respiration, ECG, sleep variables, EEG), challenge of ventilation during sleep, and monitoring of brain stem evoked potentials (auditory) during sleep is currently underway.